1. Field of the Invention
The present invention relates to a light emission device having a vacuum vessel and a display device using the light emission device as a light source.
2. Description of Related Art
There are many different types of light emission devices that can radiate visible light. One type of light emission device includes a structure in which electron emission regions and driving electrodes are disposed on a first substrate, and a phosphor layer and an anode electrode are disposed on a second substrate. The first and second substrates are sealed to each other at their peripheries using a sealing member, and the inner space between the first and second substrates is exhausted to form a vacuum vessel (or a vacuum chamber).
In operation, the electron emission regions emit electrons toward the phosphor layer, and the electrons excite the phosphor layer to cause it to emit visible light. An emission amount of the electrons is controlled by driving voltages applied to the driving electrodes. The anode electrode receives a high voltage of a few thousand volts to accelerate the electrons toward the phosphor layer.
When the vacuum vessel is in a high vacuum state, emission efficiency and durability of the electron emission regions can be improved. Therefore, a getter unit is provided inside the vacuum vessel. After an exhaust process of the vacuum vessel, a getter activating process is conducted to cause the inner space of the vacuum vessel to be in the high vacuum state. The getter activating process includes activating a getter material and chemically adsorbing gaseous molecules remaining within the vacuum vessel.
In a conventional light emission device, the getter unit may be located between the first and second substrates at a non-active area at which the driving electrodes and the phosphor layer are not formed. Alternatively, the getter unit may be located inside a getter chamber that is attached to the first substrate at the non-active area. The inner space of the getter chamber is connected to the inner space of the vacuum vessel.
However, in a case where an evaporating getter unit is located between the first and second substrates at the non-active area, a conductive getter material may be diffused into an active area on which the driving electrodes and the phosphor layer are formed. Accordingly, this may cause a short circuit between adjacent driving electrodes and damage to the phosphor layer.
In addition, in a case where the getter unit is located inside of the getter chamber, manufacture of the vacuum vessel is complicated by adding a hole-forming process on the first substrate where the getter chamber is to be attached and the getter chamber sealing process on an exterior of the first substrate.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.